The present invention relates to automated tape library machines used for mass storage of data, and more particularly to an improved access port which allows removal of a tape cartridge while minimizing the risk of operator injury.
Automated tape library machines have been used to greatly increase the efficiency and ease at which large quantities of data, such as generated by a computer network, can be stored and accessed by external host systems. Such machines are well known in the art, and generally include a robotic unit that moves within a housing under control of a microprocessor to retrieve and load desired tape cartridges into a tape drive unit. These machines further include an access port, or customer access port (CAP), arranged to allow a user to insert and remove data storage cartridges into the automated tape library machine without taking the entire machine off-line.
The mechanical design of a CAP for any given tape library machine must satisfy a wide variety of design factors relating to particular functional, safety, aesthetic, economic, and reliability requirements. Of these design factors, safety is perhaps the most important. In other words, a CAP must be arranged so that an operator is never in danger of contacting any moving robotic mechanisms within the library. Known CAP arrangements typically provide an input slot for receiving a cartridge from the customer, and a mechanism that subsequently moves the inserted cartridge from the input slot into engagement with the robotic tape system. Other arrangements use a tape loading and unloading mechanism that rotates one or more inserted tape cartridges from a position in which the tapes face outwardly through an opening in the library housing, to a position in which the tapes face inwardly so as to be accessible by a transport/robotic mechanism. An example of such a rotary arrangement is provided in U.S. Pat. No. 4,779,151 to Lind et al.
However, known CAP arrangements that use mechanisms to transport a tape from a user accessible position to a robot accessible position typically suffer the drawback of requiring expensive and complicated mechanical arrangements in order to meet high speed tape loading/de-loading and reliability demands. Therefore, a need exists for a simple access port arrangement which is both reliable and does not compromise customer/user safety.
It is therefore an object of the present invention to provide an automatic access port for a tape library machine that prevents any potential contact between an operator and a robotic mechanism located inside the machine during loading and unloading of tape cartridges.
It is another object of the present invention to provide an automatic access port for a tape library machine which utilizes two separate but interlocking doors which latch and unlatch in a controlled manner about a stationary tape cartridge retainer mechanism so as to prevent any potential contact between the operator and a robot mechanism within the library.
In accordance with these and other objects, the present invention provides an access port mounted to an automated tape cartridge library housing for allowing insertion and removal of tape cartridges from the library that includes a cartridge access opening formed in the library housing, an outer door externally mounted to the housing so as cover the cartridge access opening in a closed position, and a rotatable inner door mounted to the inside of the housing in alignment with the cartridge access opening. A latch arrangement is mounted to the inner and outer doors which only unlatches the outer door when the inner door is in a closed position.
In accordance with one embodiment of the present invention, the inner rotatable door includes a stationary frame which defines a cavity within the access opening and is arranged to support placement of a stationary cartridge retainer mechanism therein. The inner door can include a drive arrangement which prevents manual opening of the inner door.
Thus, in accordance with one aspect of the present invention, a double-door safety access port is provided as a simple and safe mechanism for allowing an operator to insert and remove cartridges from a library machine without requiring the machine to be taken off-line. The two doors operate independently, but are interconnected mechanically with a latch mechanism and electrically through at least one electrical switch, to allow a library machine to control customer access to the access port. In addition, because the retainer mechanism is allowed to be stationary, the cartridges are inserted and removed with their labels facing the robot side of the access port and remain fixed in respective cell or slot positions during operation of the access port doors. The inner door of the access port is motor-driven between an open position allowing robot access to the cartridges, and a closed position to provide a physical barrier between the inside of the labeling machine and an operator. The outer door allows operator access to the tape cartridges when in an open position, but can not be unlatched and opened if the inner door is not fully closed. An inner door driving mechanism preferably includes a self-locking worm gear to render the inner door moveable only by operation of the motor. This prevents any manual rotation of the inner door by an operator. The inter-latching mechanism between the inner and an outer door is responsive to the inner door being in the closed position to unlatch or release the outer door. Once the outer door is unlatched, an operator can access cartridges loaded in the access port. The outer door is closed manually by the operator to a latched position, and once latched, the inner door can be driven back to its open position by operation of the motor. The inter-latching of the inner door and outer door insures that the inside of the library machine is always closed off to access by an operator to prevent any possibility of operator contact with the library robot.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.